Einstein

applies his great formula to the problem of determining the mass of a photon.

E = M C2

This familiar equation is actually a special case of the equation Einstein discovered.

It is the special case where the object in question (which we wish to calculate the total energy available) is at rest

Energy = MC2/Sqrt ( 1 - v2/c2)

The last part of the equation tells us that the Energy of an object increases if the object is traveling a velocity of v.

In particular, if the object in question is standing still, (v=0) the equation reduces to the familiar E=mc2 .

Einstein almost never wrote out his famous formula. E=mc2 .

Thus, the page you are looking is one of the great treasures of the scientific world.